The present invention is directed generally to rotary driven cylindrical cutters and scarifiers for use in earthworking, mining, or other in situ disintegration of hard materials. The invention is particularly directed to such rotary driven cylindrical cutters and scarifiers which have the tool blocks mounted directly onto the flighting or directly to the surface of the cylindrical cutter.
The invention has particular utility in connection with cutting bits and blocks. Examples of the prior art are to be found in Kniff U.S. Pat. No. 3,820,848; Kniff U.S. Pat. No. 3,830,546; Kniff et al U.S. Pat. No. 3,841,707; Wrulich et al. U.S. Pat. No. 4,159,746; Wrulich et al. U.S. Pat. No. 4,247,150; Krekeler U.S. Pat. No. 4,337,980; LeBegue et al. U.S. Pat. No. 4,299,424; Latham U.S. Pat. No. 4,480,873; Penkunas et al. U.S. Pat. No. 4,725,099.
In general, the construction blocks disclosed in the prior art includes a recess to accept a rotary mining or construction tool. Tool bits are removably mounted within the recesses in such a way that the edge of the tool bit projects outward beyond the side of the tool block. The projection of the tool bit causes it to rotate in the recess of the construction blocks. Sometimes a rotating wear guard may be incorporated with the tool bit or the construction block.
In use, the abrasive forces, which often include sudden rather high value shocks, are transmitted from the cutting bits into the construction blocks. The forces frequently become large enough to wear the recess of the construction blocks. The recess becomes too large to hold the cutting bit, causing the machine to be stopped for construction block replacement. Also, when the tooth does break off, the seat of the block is wiped out. The repair and replacement of the tool block member damaged in either manner typically necessitates the use of a cutting torch to remove construction blocks and a welder to replace the construction in the field. This time-consuming repair job results in considerable expense to the road-mining machine operator for down time and labor. Missalignment of the support block results in undersirable lateral forces on a new cutting bit which in turn results in very fast wear and ultimate failure of the replaced parts.